essay 35 - endodontic access - goals. The endodontic cavity shape in different tooth groups

what is endodontic access?

• refers to the creation of an opening in the crowns of a tooth to allow the dentist to locate, clean, shape, disinfect and obturate (fill) the root canal system. It is a critical first step in endodontic treatment

goals (requirements) of endodontic access

1. complete removal of chamber contents

• total removal of the pulp chamber roof allows thorough cleaning of the chamber, pulp horns and calcification

• prevents persistent infection or discolouration

2. direct vision of pulp floor and canal orifices

• visibility of the entire floor is crucial for locating canal opening

• grooves and natural landmarks guide orifice location

3. facilitates insertion of instruments

• well shaped cavity helps canal instrument glide into the canals without obstruction

• smooth entry reduces the risk of ledges, blockages or instrument fracture

4. straight-line access to the apical third

• instruments must reach the apical third without being deflected

• prevents deforming of apical foramen and improves instrument control

5. support for temporary fillings

• slight flaring of cavity walls gives mechanical retention for temporary fillings

• prevents leakage and contamination between appointments

6. leave four stable walls

• helps in rubber dam placement, irrigation retention, reference points for instrumentation and safe medication placement

rules to follow during endodontic access

1. orientation of apical foramen = creating the access cavity, one must keep in mind not only the position of the canal orifices, but also the orientation of the apical foramen. In markedly curved canals, the access cavity must be extended opposite to the curve to reduce instrument bending

2. different from restorative cavity = the shape differs from restorative dentistry; endodontic access must uncover the pulp by removing the chamber roof for straight access to apical foramen.

3. Anatomy determines shape = the cavity must not have predetermined shape. Its form - triangular, elliptical or trapezoidal - depends on the pulp chamber floor anatomy

4. Know anatomy = this is essential, gained through clinical observation and radiographs in multiple views

5. Rubber dam timing = when canals are difficult to find, begin without the rubber dam until the canals are located

6. correct access location = access should always be through the occlusal or lingual surface, not approximate or gingival